Anil Kumar, Manish Sainger, Ranjana Jaiwal, Pawan K. Jaiwal and Darshna Chaudhary
Centre for Biotechnology, Maharshi Dayanand University, Rohtak-124 001 (Haryana), India
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(Received : August 21, 2020; Accepted : October 17, 2020)
An efficient and reproducible in vitro multiple shoot induction and plant regeneration system in cowpea was successfully developed from cotyledonary node explants. The factors affecting in vitro multiple shoot regeneration were optimized. Different cytokinins, concentration of 6-benzylaminopurine (BAP), preconditioning and the age of the explants influenced the frequency of shoot formation and the number of shoots per explant. Explants cultured on MSB basal medium produced a single or two shoots, whereas those cultured on BAP induced multiple shoots. This indicated that BAP was significant for multiple shoot proliferation. Replacing BAP with different cytokinins at an equimolar concentration significantly reduced the shoot number. The pre-conditioning of explants also affected the multiple shoot regeneration response. The cotyledonary node explants excised from in vitro raised seedling on 10 µM BAP for 4-day
old and cultured on MS salts with B5 vitamins (MSB) medium having 5.0 µM BAP produced a maximum of 6-7 shoots per explant in 94% of the cultures. In vitro developed shoots were successfully rooted on MS medium supplemented with IBA (1.5 µM) and plantlets were acclimatized in the earthen pots having soil rite. In vitro raised plants were morphological normal plants with viable seeds and produced within two months from initiation of cultures to establishment of plants in soil.
Key words : In vitro regeneration, cowpea, cotyledonary node explants